Typhoon Koppu, known as "Lando" in the Philippines, reached Casiguran in Luzon's Aurora province at 1 a.m. local time Sunday morning (1 p.m. Saturday ET). There were reports of power outages and even before the storm hit, its outer bands drenched the country's east coast with heavy rains.

The center of the typhoon was over Pantabangan, Nueva Ecija and was moving north-northwest at around 3 mph as of 10 a.m. local time Sunday, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).

The typhoon had sustained winds of around 93 mph and gusts of up to 114 mph, the administration said. The slow movement of the typhoon caused fears that the damage could be greater as the storm lingers.

"It has slowed almost to a crawl. We're hoping it would speed up and spare us sooner," Alexander Pama, who heads the government's main disaster agency that has overseen evacuation and pre-deployment of rescue contingents, told The Associated Press.

"Initially, we are getting many houses were destroyed, power lines toppled and trees blocking major roads," he told Reuters, adding 10,000 people had been displaced in northeastern Luzon, the country's main island.

If you are advised to vacate the area, or if you think you are in danger, evacuate immediately away from #LandoPH 's direction of movement.

The U.S. military's Joint Typhoon Warning Center upgraded Koppu to a super typhoon — a term for typhoons with maximum winds of at least 150 mph, the equivalent of a Category 4 hurricane — on Saturday. Koppu is the strongest typhoon to make landfall in Luzon in five years, The Weather Channel reported.

Residents in Aurora, the city of Santiago and the province of Quirino had already reported power outages Sunday morning, according to the Philippine Red Cross.

The biggest threat from the typhoon was expected to be its "catastrophic flood threat" from a multi-day deluge, the Weather Channel said.

Weather Channel senior digital meteorologist Nick Wiltgen predicted "prolific rainfall as it grinds across the mountains and valleys of Luzon ... [which is] home to almost half of the country's 98 million people." Luzon could receive up to six days of heavy rainfall, he added, with 20 to 40 inches of rain possible.

In certain areas, depending on the track of the storm, nearly 80 inches "would not be unrealistic," Wiltgen said. Meanwhile, in the densely populated metro Manila area, home to some 12 million residents, more than a foot of rain could fall, triggering flash flooding.

The Philippine weather agency PAGASA warned Koppu's eyewall could cause heavy damage to structures and crops. PAGASA said the storm was delivering winds of more than 100 mph in Aurora early Sunday morning local time.

On Friday, President Benigno Aquino III, in a nationally televised address, warned that about 7.5 million people would likely need help during and after the storm. It was the first time since Typhoon Haiyan hit the country, leaving more than 7,300 people dead and missing, that he had issued a national storm warning.